Mismatch Repair Deficiency, Microsatellite Instability, and Survival: An Exploratory Analysis of the Medical Research Council Adjuvant Gastric Infusional Chemotherapy (MAGIC) Trial

Importance: Mismatch repair (MMR) deficiency (MMRD) and microsatellite instability (MSI) are prognostic for survival in many cancers and for resistance to fluoropyrimidines in early colon cancer. However, the effect of MMRD and MSI in curatively resected gastric cancer treated with perioperative chemotherapy is unknown. Objective: To examine the association among MMRD, MSI, and survival in patients with resectable gastroesophageal cancer randomized to surgery alone or perioperative epirubicin, cisplatin, and fluorouracil chemotherapy in the Medical Research Council Adjuvant Gastric Infusional Chemotherapy (MAGIC) trial. Design, Setting, and Participants: This secondary post hoc analysis of the MAGIC trial included participants who were treated with surgery alone or perioperative chemotherapy plus surgery for operable gastroesophageal cancer from July 1, 1994, through April 30, 2002. Tumor sections were assessed for expression of the MMR proteins mutL homologue 1, mutS homologue 2, mutS homologue 6, and PMS1 homologue 2. The association among MSI, MMRD, and survival was assessed. Main Outcomes and Measures: Interaction between MMRD and MSI status and overall survival (OS). Results: Of the 503 study participants, MSI results were available for 303 patients (283 with microsatellite stability or low MSI [median age, 62 years; 219 males (77.4%)] and 20 with high MSI [median age, 66 years; 14 males (70.0%)]). A total of 254 patients had MSI and MMR results available. Patients treated with surgery alone who had high MSI or MMRD had a median OS that was not reached (95% CI, 11.5 months to not reached) compared with a median OS among those who had neither high MSI nor MMRD of 20.5 months (95% CI, 16.7-27.8 months; hazard ratio, 0.42; 95% CI, 0.15-1.15; P\u2009=\u2009.09). In contrast, patients treated with chemotherapy plus surgery who had either high MSI or MMRD had a median OS of 9.6 months (95% CI, 0.1-22.5 months) compared with a median OS among those who were neither high MSI nor MMRD of 19.5 months (95% CI, 15.4-35.2 months; hazard ratio, 2.18; 95% CI, 1.08-4.42; P\u2009=\u2009.03). Conclusions and Relevance: In the MAGIC trial, MMRD and high MSI were associated with a positive prognostic effect in patients treated with surgery alone and a differentially negative prognostic effect in patients treated with chemotherapy. If independently validated, MSI or MMRD determined by preoperative biopsies could be used to select patients for perioperative chemotherapy

Sequence variation in mature microRNA-608 and benefit from neo-adjuvant treatment in locally advanced rectal cancer patients

Single nucleotide polymorphisms (SNPs) in microRNA genes have been associated with colorectal cancer (CRC) risk, survival and response to treatment. Conflicting results are available on the association between rs4919510, a SNP in mature miR-608 and clinical outcome in CRC. Here, we analyzed the association between rs4919510 and benefit from perioperative treatment in a randomised phase II trial of neoadjuvant Capecitabine and Oxaliplatin (CAPOX) followed by chemo-radiotherapy, surgery and adjuvant CAPOX ± Cetuximab in high-risk locally advanced rectal cancer (LARC). A total of 155/164 (94.5%) patients were assessable. 95 (61.3%) were homozygous for CC, 55 (35.5%) heterozygous (CG) and 5 (3.2%) homozygous for GG. Median follow-up was 64.9 months. In the CAPOX arm the 5-year progression-free survival (PFS) and overall survival (OS) rates were 54.6% and 60.7% for CC and 82.0% and 82.1% for CG/GG, respectively (HR PFS 0.13, 95% CI: 0.12-0.83, P = 0.02; HR OS 0.38, 95% CI: 0.14-1.01, P = 0.05). In the CAPOX-C arm PFS and OS were 73.2 and 82.2%, respectively for CC carriers and 64.6 and 73.1% for CG/GG carriers (HR PFS 1.38, 95% CI: 0.61-3.13, P = 0.44; HR OS 1.34, 95% CI: 0.52-3.48, P = 0.55). An interaction was found between study treatment and rs4919510 genotype for both PFS (P = 0.02) and OS (P = 0.07). This is the first study investigating rs4919510 in LARC. The CC genotype appeared to be associated with worse prognosis compared to the CG/GG genotype in patients treated with chemotherapy and chemo-radiotherapy alone. Addition of Cetuximab to chemotherapy and chemo-radiotherapy in CC carriers appeared to improve clinical outcome

EGFR amplification and outcome in a randomised phase III trial of chemotherapy alone or chemotherapy plus panitumumab for advanced gastro-oesophageal cancers.

Funder: FP7 People: Marie-Curie Actions; FundRef: http://dx.doi.org/10.13039/100011264; Grant(s): CIG 334261OBJECTIVE: Epidermal growth factor receptor (EGFR) inhibition may be effective in biomarker-selected populations of advanced gastro-oesophageal adenocarcinoma (aGEA) patients. Here, we tested the association between outcome and EGFR copy number (CN) in pretreatment tissue and plasma cell-free DNA (cfDNA) of patients enrolled in a randomised first-line phase III clinical trial of chemotherapy or chemotherapy plus the anti-EGFR monoclonal antibody panitumumab in aGEA (NCT00824785). DESIGN: EGFR CN by either fluorescence in situ hybridisation (n=114) or digital-droplet PCR in tissues (n=250) and plasma cfDNAs (n=354) was available for 474 (86%) patients in the intention-to-treat (ITT) population. Tissue and plasma low-pass whole-genome sequencing was used to screen for coamplifications in receptor tyrosine kinases. Interaction between chemotherapy and EGFR inhibitors was modelled in patient-derived organoids (PDOs) from aGEA patients. RESULTS: EGFR amplification in cfDNA correlated with poor survival in the ITT population and similar trends were observed when the analysis was conducted in tissue and plasma by treatment arm. EGFR inhibition in combination with chemotherapy did not correlate with improved survival, even in patients with significant EGFR CN gains. Addition of anti-EGFR inhibitors to the chemotherapy agent epirubicin in PDOs, resulted in a paradoxical increase in viability and accelerated progression through the cell cycle, associated with p21 and cyclin B1 downregulation and cyclin E1 upregulation, selectively in organoids from EGFR-amplified aGEA. CONCLUSION: EGFR CN can be accurately measured in tissue and liquid biopsies and may be used for the selection of aGEA patients. EGFR inhibitors may antagonise the antitumour effect of anthracyclines with important implications for the design of future combinatorial trials

KRAS and BRAF mutations in circulating tumour DNA from locally advanced rectal cancer

Abstract There are limited data on circulating, cell-free, tumour (ct)DNA analysis in locally advanced rectal cancer (LARC). Digital droplet (dd)PCR was used to investigate KRAS/BRAF mutations in ctDNA from baseline blood samples of 97 LARC patients who were treated with CAPOX followed by chemoradiotherapy, surgery and adjuvant CAPOX ± cetuximab in a randomised phase II trial. KRAS mutation in G12D, G12V or G13D was detected in the ctDNA of 43% and 35% of patients with tumours that were mutant and wild-type for these hotspot mutations, respectively, according to standard PCR-based analyses on tissue. The detection rate in the ctDNA of 10 patients with less common mutations was 50%. In 26 cases ctDNA analysis revealed KRAS mutations that were not previously found in tissue. Twenty-two of these (84.6%) were detected following repeat tissue testing by ddPCR. Overall, the ctDNA detection rate in the KRAS mutant population was 66%. Detection of KRAS mutation in ctDNA failed to predict prognosis or refine patient selection for cetuximab. While this study confirms the feasibility of ctDNA analysis in LARC and the high sensitivity of ddPCR, larger series are needed to better address the role of ctDNA as a prognostic or predictive tool in this setting

FcγRIIa and FcγRIIIa polymorphisms and cetuximab benefit in the microscopic disease

Purpose: Fc gamma R polymorphisms have been reported to enhance the immune-mediated effects of cetuximab in metastatic colorectal cancer. There are no data on the relationship between these polymorphisms and cetuximab in the early-stage setting. We performed a pharmacogenomic analysis of EXPERT-C, a randomized phase II trial of neoadjuvant CAPOX followed by chemoradiotherapy, surgery, and adjuvant CAPOX +/- cetuximab in high-risk, locally advanced rectal cancer. Experimental Design: Fc gamma RIIa-H131R and Fc gamma RIIIa-V158F polymorphisms were analyzed on DNA from peripheral blood samples. Kaplan-Meier method and Cox regression analysis were used to calculate survival estimates and compare treatment arms. Results: Genotyping was successfully performed in 105 of 164 (64%) patients (CAPOX = 54, CAPOX-C = 51). No deviation fromthe Hardy-Weinberg equilibrium or association of these polymorphisms with tumor RAS status was observed. Fc gamma RIIa-131R (HR, 0.38; P = 0.058) and Fc gamma RIIIa-158F alleles (HR, 0.21; P = 0.007) predicted improved progression-free survival (PFS) in patients treated with cetuximab. In the CAPOX-C arm, carriers of both 131R and 158F alleles had a statistically significant improvement in PFS (5 years: 78.4%; HR, 0.22; P = 0.002) and overall survival (OS; 5 years: 86.4%; HR, 0.24; P = 0.018) when compared with patients homozygous for 131H and/or 158V (5-year PFS: 35.7%; 5-year OS: 57.1%). An interaction between cetuximab benefit and 131R and 158F alleles was found for PFS (P = 0.017) and remained significant after adjusting for prognostic variables (P = 0.003). Conclusion: This is the first study investigating Fc gamma RIIa and Fc gamma RIIIa polymorphisms in patients with early-stage colorectal cancer treated with cetuximab. We showed an increased clinical benefit from cetuximab in the presence of 131R and 158F alleles. (C) 2014 AACR